div{
width:100px;
height: 50px;
border: 2px dotted red;
border-radius: 50% 50% 0 0 / 100% 100% 0 0;
border-bottom:none;
position:relative;
color:red;
transition: 3s all ease;
transform-origin: 50% 100%;
}
div:after{
position:absolute;
content:'▼';
bottom:-10px;
right:-11px;
transform: rotate(-38deg);
}
div:before{
position:absolute;
content:'▼';
bottom:-10px;
left:-11px;
transform: rotate(38deg);
}
div:hover {
transform: rotateZ(360deg)
}